I am planning to make a Plagiarism Detector as my Computer Science Engineering final year project,for which I would like to take your suggestions on how to go about it.
I would appreciate if you could suggest which all fields in CS I need to focus on and also the language which would be the most appropriate to implement in.
The language is nearly irrelevant. Another questions exists that discusses this a bit more. Basically, the method suggested there is to use Google. Extract parts of the target-text, and search for them on Google.